GTK+ 2 Rawtherapee backport for Debian Jessie
The GTK+ 3 version requires a minimum of version 3.16, and Jessie has only 3.14. Rawtherapee offers a GTK+ 2 source download that will build on Jessie. However, it also requires a minimum gcc version 4.9, so that rules it out for Wheezy and Ubuntu Trusty. The repo also contains an unrelated backport of Unetbootin.